A Convenient Synthesis of Furanose‐Free D ‐Fucose Per‐ O ‐Acetates and a Precursor for Anthrose

Methyl 3,4‐ O ‐isopropylidene‐α‐ or β‐ D ‐galactopyranoside was iodinated with triiodoimidazole in the presence of triphenylphosphane and the corresponding 6‐deoxy‐6‐iodo derivatives 5 or 6 , respectively, were converted to furanose‐free 1,2,3,4‐tetra‐ O ‐acetyl‐α,β‐ D ‐fucopyranose. A key intermediate for chemical synthesis of anthrose, a constituent of the tetrasaccharide of major glycoprotein of Bacillus anthracis exosporium, 1‐ O ‐acetyl‐4‐azido‐2‐ O ‐benzoyl‐3‐ O ‐benzyl‐4,6‐dideoxy‐α,β‐ D ‐glucopyranose, was synthesized from 5 or 6 in 7 steps. The latter was readily converted into the corresponding 1‐ O ‐trichloroacetimidate.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)